Strange input allowed in single-argument function shorthand

[imm]

After looking at the fun uses of await and delete that we get after #883, I found that civet accepts this kind of input

x.filter not.condition
x.forEach delete.old

↓↓↓

x.filter(($) => !$.condition);
x.forEach(($1) => delete$1.old);

In my opinion either this should be invalid syntax or there should be a space after delete

This trick doesn't work with await:

x.map await.json()
                 ^ ParseError

[edemaine]

Thanks for spotting this so quickly! Should be fixed by #886.